Acute inhalation toxicity was evaluated in groups of 5 male and 5 female Sprague-Dawley albino rats exposed to Aerothene TT (1,1,1-trichloroethane) as a vapor (dynamically-generated) at an actual concentration of 34,134 mg/cubic meter or as a vapor/aerosol (fine mist sprayed into a pre-atomization chamber) at an actual concentration of 19,265 mg/cubic meter for 4 hours. Mortality was observed in 4 males and 3 females in the vapor/aerosol dose group (19,265 mg/cubic meter). An LC50 value was not reported. Clinical observations included hypoactivity in animals exposed to the vapor and abdominal breathing, decreased respiration rate and hypoactivity in animals exposed to the vapor/aerosol. Gross necropsy revealed dark red discoloration of the lungs, fluid in the thoracic cavity and trachea, red perinasal, perioral, or periocular encrustation, and gas-filled intestines in decedents.